Prediction of Chronic Vessel Enlargement by a Novel Intravascular Ultrasound Finding

Abstract

A total of 27 patients who underwent successful IVUS-guided percutaneous coronary intervention (PCI) for severe coronary stenosis were retrospectively selected and enrolled from our IVUS database. Inclusion criteria were lesions with chronic total occlusion (CTO) or severely stenotic lesions (%diameter stenosis >90% and delayed distal flow) with angiographic follow-up at 9 months. Exclusion criteria were culprit lesions for acute myocardial infarction, lesions without final IVUS imaging of the distal reference segments and presence of target lesion restenosis or re-occlusion at follow-up. All patients gave written informed consent. Angiography and Interventional ProceduresAfter intravenous or intraarterial bolus injection of heparin (5,000-10,000 units), coronary angiography (CAG) and the PCI were performed by standard femoral or radial approach oronary arterial segments distal to the severely stenotic or occluded lesion usually shrink as a result of chronically decreased coronary flow. Although differentiation of residual organic stenosis and vessel shrinkage that has the potential to reverse 1 without additional intervention is clinically important in the catheterization laboratory, no specific angiographic, intravascular ultrasonographic or optical coherence tomographic 2-4 findings have been shown.Recent pathological studies have suggested that vessel spasm or shrinkage is accompanied by folding of the internal elastic membrane (IEM). 5,6 Intravascular ultrasound (IVUS) may visualize the folding of the IEM as a high-echoic band and thus could detect chronically shrunken vessels that have potential to enlarge late after revascularization.We hypothesized that a novel IVUS finding, a peri-medial high-echoic band (PHB), would predict chronic vessel enlargement of the distal coronary segments after intervention of the severely stenotic proximal target lesion.

Novel predictors of late lumen enlargement in distal reference segments after successful recanalization of coronary chronic total occlusion

“…Lumen gain (LG), which represents late lumen enlargement, was defined an increase in the LD of the segment 5 mm distal to the implanted stent from post‐PCI to follow‐up. %LG was calculated as ([LD at follow‐up] – [LD at post‐PCI])/(LD at post‐PCI) × 100 (Figure ) . Study population was classified into three groups according to the tertiles of %LG.…”

“…We included variables with a p ‐value of <0.05 on univariable analysis to conduct multivariable analysis by multiple linear regression analysis. The receiver operating characteristics (ROC) curve analysis was carried out on the basis whether %LG is more than 10% or not . The area under the curve (AUC) of the ROC curve was compared using the Delong method.…”

“…%LG was calculated as ([LD at follow-up] -[LD at post-PCI])/(LD at post-PCI) × 100 ( Figure 1). 8 Study population was classified into three groups according to the tertiles of %LG. Calcification was identified as readily apparent radiopacities within the vascular wall at the site of the occlusion and was classified as none/mild, moderate (radiopacities noted only during the cardiac cycle before contrast injection), and severe (radiopacities noted without cardiac motion before contrast injection generally compromising both sides of the arterial lumen).…”

“…However, the predictor of the late lumen enlargement of segments located distal to successfully recanalized CTO is not fully understood. The differentiation of residual stenosis that cannot be enlarged spontaneously and vessel shrinkage which has the potential to reverse by improvement of distal blood flow is clinically important, in order to avoid unnecessary intervention to the distal segment . The aim of this study was to assess the extent and predictors of the late lumen enlargement in distal segment after successful CTO PCI at follow‐up.…”

“…6,7 However, the predictor of the late lumen enlargement of segments located distal to successfully recanalized CTO is not fully understood. The differentiation of residual stenosis that cannot be enlarged spontaneously and vessel shrinkage which has the potential to reverse by improvement of distal blood flow is clinically important, 5,8 in order to avoid unnecessary…”